"Uncover Black's Identity! To the Sacred World of the Kais!" (ブラックの正体を暴け! いざ第10宇宙の界王神界へ!, Burakku no shōtai o abake! Iza dai 10 uchū no kaiōshin kai e!) is the fifty-third episode of Dragon Ball Super. Its Japanese air date is July 31st, 2016.
Goku, Beerus, and Whis head off to the Sacred World of the Kais of Universe 10. Whis has an idea that he knows Black's true identity and reveals that Zamasu is a Kai who is a fighting genius and the apprentice to Gowasu, the Supreme Kai of Universe 10. Goku becomes excited at challenging him while irritating Beerus so much that he threatens to push him off. Meanwhile, when pouring tea for Gowasu, Zamasu strikes up a conversation with him about humans. He says that he wants to destroy them, but Gowasu says that isn't his decision and that Kais are not allowed to interfere with creation. Whis, Beerus, and Goku arrive at the Sacred World of the Kais and Zamasu is surprised at Goku for being on the Sacred World. Whis notes this is the first time he has ever met Goku. Zamasu clearly doesn't want him there and almost attacks Goku, but Gowasu stops him from doing it and pardons him.
Once that is done, Whis gets Gowasu up to speed about Black and was telling him that he was no kai and possessed a time ring. Zamasu didn't know about time rings yet, it seems. Beerus then tells Gowasu that Black looked a lot like Goku, surprising him at this. Beerus asks where he keeps the time rings and Gowasu says that they are in the temple. Beerus wanted a confirmation so Gowasu made Zamasu lead Beerus, Whis, and Goku to the temple and the time rings were there. Goku continues to beg Zamasu to fight him who says no. However, to Zamasu's dismay, Gowasu insists Zamasu fight him, telling him it's apart of his training. Gowasu says Zamasu should hold back, but Beerus tells him it will cost him his life if he does so. Future Trunks and Krillin talk about families and Krillin tells him about his daughter, but is reluctant to tell him about his wife. When 18 shows up brining their daughter to him, after revealing that she had been worried about him. Upon seeing her, Future Trunks begins pulling out his sword until Krillin intervenes. 18 steps over to Future Trunks, informing him that she had heard of him killing her counterpart in his timeline and that she wants reimbursements, before revealing that she is joking and rejoining her daughter and husband. Future Trunks watches her interact with her family with a strange expression on his face before he goes to speak with his mother. The battle starts off with Goku going Super Saiyan 2 against Zamasu. Both Gowasu and Zamasu are both surprised when they see this and Whis tells Gowasu that it is a Super Saiyan. Zamasu was wondering how humans had that power. Goku tells him that he hasn't fought a god since Beerus and Zamasu is very surprised at this development. Once the battle begins, Goku throws a punch at Zamasu, who catches it and throws it to the side. Zamasu throws a chop to the neck, but Goku rebounds an energy ball at his hand. Then Goku, Beerus, and Whis notices the similarities between Zamasu's and Black's ki. Goku then begins pushing Zamasu back, and Zamasu questions how could a mortal be this strong. Goku delivers a swift punch to end the match and compliments Zamasu for how strong he was. Zamasu was about to attack Goku but Gowasu stopped him. Beerus yawns and gets ready to go home since he saw the rings.
On the way home, Whis says Zamasu was suppressing his cold heart and it showed enough evidence to prove Zamasu was Black. Beerus says he should have destroyed him, but Goku says he wasn't such a bad guy, causing Beerus to say that Goku is too trusting. While they were walking back to the celestial tree, Gowasu asks Zamasu if he has cleared the distrust of mortals in his heart, but Zamasu says that he is ashamed at his inadequacy. While Zamasu is pouring tea for Gowasu, he says he will never forget Goku.
- Goku (Super Saiyan 2) vs. Zamasu